package facade;

/**
 * @author shenhan
 * @create 2020/4/3 16:18
 * @description
 */
public class Screen {
    private static Screen instance = new Screen();

    public static Screen getInstance() {
        return instance;
    }

    public void up() {
        System.out.println("屏幕 上升");
    }

    public void down() {
        System.out.println("屏幕 下降");
    }


}
